Rapid technological developments in the electronics and computer industry have created a large consumer market for a variety of batteries. For example, batteries are used to power almost every portable electronic device, such as cell phones, laptop computers, camcorders, portable radios, cameras, etc. Consequently, the demand for compact, high-energy density batteries has been steadily increasing.
Nickel (III) oxide/hydroxide (NiOOH) is often used as the positive electrode, e.g. the cathode, in batteries and capacitors. When a battery is discharged, nickel (III) oxide-hydroxide is reduced to nickel(II) hydroxide. When the battery is overcharged, oxygen is produced at the nickel electrode and may recombine with any hydrogen present to form water. The simplified, representative electrochemical reactions at a nickel oxide/hydroxide electrode are as follows:2NiOOH+2H2O+2e−→2Ni(OH)2+2OH−  Discharge:2Ni(OH)2+2OH—→2NiOOH+2H2O+2e−  Charge:2OH—→½O2+H2O+2e−  Overcharge:
However, conventional nickel oxide-hydroxide electrodes generally exhibit a serious deficiency with regard to charge retention.